THE USER OF ADSORPTION FOR PURIFICATION OF WASTEWATER FROM THE PRODUCTION OF PHENOL-FORMALDEHYDE RESINS

To increase ecological safety of phenol-formaldehyde resins production of the novolac type, the adsorption technology for purification of wastewater containing mainly phenol and formaldehyde was developed. The research of organic substances adsorption (formaldehyde, phenol) from individual aqueous solutions and their mixtures on carbon sorbents grades AG-3, AG-OV-1, SKD-515, BAU, ABG, XAU was conducted, this grades differ in composition, method of producing, structure, and chemical state of the surface. The basic laws, characteristics and mechanism of adsorption of organic substances on activated carbon (AU) were established. The mechanism of mass transfer during adsorption of a mixture of phenol and formaldehyde on the investigated sorbents was showed, and the external mass transfer coefficients were calculated. There was proposed the method of optimization of parameters and continuous adsorption treatment process modes, based on the fundamental external diffusion dynamics adsorption formula using the adsorption constants of the Dubinin-Radushkevich’s equation and kinetic dependencies. The main features of the adsorption dynamics were established, which allowed to determine the duration of column operation, the amount of feed water depending on the throughput rate, the height of the fixed bed and size of the column. According to the results of experimental studies and derivatographic analysis we developed the technology of carbon sorbents regeneration after adsorption of formaldehyde and phenol mixture, which allowed to restore the AC (activated carbon) sorption capacity to 95-98%. On the basis of aggregate balance studies, kinetics and dynamics of adsorption process, optimization of the cleaning regime and the parameters of adsorption column using mathematical modeling, we recommend the technological solution for waste water purification from phenol and formaldehyde, which are formed in the process of phenol-formaldehyde resins of the novolac type production.